Image transfer process employing a hard mask layer

ABSTRACT

At least one mask layer formed over a substrate includes at least one of a dielectric material and a metallic material. By forming a first pattern in one of the at least one mask layer, a patterned mask layer including said first pattern is formed. An overlying structure including a second pattern that includes at least one blocking area is formed over said patterned mask layer. Portions of said patterned mask layer that do not underlie said blocking area are removed. The remaining portions of the patterned mask layer include a composite pattern that is an intersection of the first pattern and the second pattern. The patterned mask layer includes a dielectric material or a metallic material, and thus, enables high fidelity pattern transfer into an underlying material layer.

BACKGROUND

The present disclosure generally relates to a process for manufacturingsemiconductor structures, and particularly to an image transfer processemploying a hard mask layer to memorize a composite pattern, andstructures for effecting the same.

A trilayer lithography process as known in the art employs an organicmaterial layer such as an amorphous carbon layer in order to transfer acomposite image of two independent images. The sidewalls of the organicmaterial layer are formed with a significant level of line edgeroughness and line width roughness during a pattern transfer etch thatforms a pattern in the organic material layer employing an overlyinglayer as a patterned mask because the organic material layer is prone tolateral etching. The line edge roughness and the line width roughness ofthe organic material layer are further increased during a subsequentpattern transfer etch that transfers the pattern in the organic materiallayer into an underlying layer employing the organic material layer asan etch mask. The increased line edge roughness and line width roughnessin the organic material layer is at least partly transferred into theunderlying layer. Thus, the fidelity of pattern transfer is degraded dueto the lateral etching of the organic material layer in the materialstack employed for the trilayer lithography process.

BRIEF SUMMARY

At least one mask layer formed over a substrate includes at least one ofa dielectric material and a metallic material. By forming a firstpattern in one of the at least one mask layer, a patterned mask layerincluding said first pattern is formed. An overlying structure includinga second pattern that includes at least one blocking area is formed oversaid patterned mask layer. Portions of said patterned mask layer that donot underlie said blocking area are removed. The remaining portions ofthe patterned mask layer include a composite pattern that is anintersection of the first pattern and the second pattern. The patternedmask layer includes a dielectric material or a metallic material, andthus, enables high fidelity pattern transfer into an underlying materiallayer.

According to an aspect of the present disclosure, a method of patterninga structure is provided. At least one mask layer including at least oneof a dielectric material and a metallic material is formed over asubstrate. A first pattern is formed in one of the at least one masklayer. A patterned mask layer including the first pattern is thusformed. An overlying structure including a second pattern over thepatterned mask layer is subsequently formed. The second pattern includesat least one blocking area. Portions of the patterned mask layer that donot underlie the blocking area are removed. Remaining portions of thepatterned mask layer include a composite pattern that is an intersectionof the first pattern and the second pattern.

According to another aspect of the present disclosure, a lithographicstructure is provided, which includes an underlying material layerlocated on a substrate, at least one mask layer including at least oneof a dielectric material and a metallic material and located over theunderlying material layer, an organic planarizing layer (OPL) locatedover the at least one mask layer, an antireflective coating (ARC) layerlocated on the OPL, and a patterned structure located over the ARClayer.

According to yet another aspect of the present disclosure, anotherlithographic structure is provided, which includes an underlyingmaterial layer located on a substrate, a patterned mask layer includingat least one of a dielectric material and a metallic material andlocated over the underlying material layer, an organic planarizing layer(OPL) located over the patterned mask layer, an antireflective coating(ARC) layer located on the OPL, and a photoresist layer located over theARC layer and including at least one opening therein.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view of a first exemplary structureafter deposition of an underlying material layer, and optionaldielectric material layer, a dielectric mask layer, a metallic masklayer, a first organic planarizing layer (OPL), a first antireflectivecoating (ARC) layer, and mandrel structures according to a firstembodiment of the present disclosure.

FIG. 2 is a vertical cross-sectional view of the first exemplarystructure after deposition of a conformal material layer according tothe first embodiment of the present disclosure.

FIG. 3 is a vertical cross-sectional view of the first exemplarystructure after formation of a set of spacer structures according to thefirst embodiment of the present disclosure.

FIG. 4 is a vertical cross-sectional view of the first exemplarystructure after removal of the mandrel structures according to the firstembodiment of the present disclosure.

FIG. 5 is a vertical cross-sectional view of the first exemplarystructure after transfer of a first pattern in the set of spacerstructures into the first ARC layer according to the first embodiment ofthe present disclosure.

FIG. 6 is a vertical cross-sectional view of the first exemplarystructure after transfer of the first pattern into the first OPLaccording to the first embodiment of the present disclosure.

FIG. 7 is a vertical cross-sectional view of the first exemplarystructure after transfer of the first pattern into the metallic masklayer according to the first embodiment of the present disclosure.

FIG. 8 is a vertical cross-sectional view of the first exemplarystructure after removal of the first OPL according to the firstembodiment of the present disclosure.

FIG. 9 is a vertical cross-sectional view of the first exemplarystructure after application of a second OPL, a second ARC layer, and afirst photoresist layer, and lithographic patterning of the firstphotoresist layer with a second pattern according to the firstembodiment of the present disclosure.

FIG. 10 is a vertical cross-sectional view of the first exemplarystructure after transferring the second pattern down to an upper portionof the second OPL according to the first embodiment of the presentdisclosure.

FIG. 11 is a vertical cross-sectional view of the first exemplarystructure after removal of the second ARC layer according to the firstembodiment of the present disclosure.

FIG. 12 is a vertical cross-sectional view of the first exemplarystructure after removal of physically exposed portions of the metallicmask layer according to the first embodiment of the present disclosure.

FIG. 13 is a vertical cross-sectional view of the first exemplarystructure after removal of the second OPL according to the firstembodiment of the present disclosure.

FIG. 14 is a vertical cross-sectional view of the first exemplarystructure application of a second photoresist layer and lithographicpatterning of the second photoresist layer with a third patternaccording to the first embodiment of the present disclosure.

FIG. 15 is a vertical cross-sectional view of the first exemplarystructure after transfer of a derived pattern which is a union of thethird pattern and a composite pattern that is an intersection of thefirst pattern and the second pattern into the dielectric mask layer andthe optional dielectric material layer according to the first embodimentof the present disclosure.

FIG. 16 is a vertical cross-sectional view of the first exemplarystructure after transfer of the derived pattern into an upper portion ofthe underlying material layer and removal of the metallic mask layeraccording to the first embodiment of the present disclosure.

FIG. 17 is a vertical cross-sectional view of the first exemplarystructure after transfer of the derived pattern to the bottom of theunderlying material layer and removal of the dielectric mask layeraccording to the first embodiment of the present disclosure.

FIG. 18 is a vertical cross-sectional view of a second exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, a metallic mask layer, a dielectric masklayer, a first organic planarizing layer (OPL), a first antireflectivecoating (ARC) layer, and mandrel structures according to a secondembodiment of the present disclosure.

FIG. 19 is a vertical cross-sectional view of the second exemplarystructure after transfer of the first pattern into the dielectric masklayer according to the second embodiment of the present disclosure.

FIG. 20 is a vertical cross-sectional view of the second exemplarystructure after transfer of the second pattern into the dielectric masklayer and removal of the second OPL according to the second embodimentof the present disclosure.

FIG. 21 is a vertical cross-sectional view of the second exemplarystructure after transfer of the derived pattern into an upper portion ofthe underlying material layer and removal of the dielectric mask layeraccording to the second embodiment of the present disclosure.

FIG. 22 is a vertical cross-sectional view of a third exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, a mask layer, a first organic planarizinglayer (OPL), a first antireflective coating (ARC) layer, and mandrelstructures according to a third embodiment of the present disclosure

FIG. 23 is a vertical cross-sectional view of the third exemplarystructure after transfer of the first pattern into the mask layeraccording to the third embodiment of the present disclosure.

FIG. 24 is a vertical cross-sectional view of the third exemplarystructure after transfer of the second pattern into the mask layer andremoval of the second OPL according to the third embodiment of thepresent disclosure.

FIG. 25 is a vertical cross-sectional view of the third exemplarystructure after transfer of the derived pattern into an upper portion ofthe underlying material according to the third embodiment of the presentdisclosure.

FIG. 26 is a vertical cross-sectional view of a fourth exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, a dielectric mask layer, a metallic masklayer, a first organic planarizing layer (OPL), a first antireflectivecoating (ARC) layer, and a photoresist layer and lithographic patterningof the photoresist layer according to a fourth embodiment of the presentdisclosure.

FIG. 27 is a vertical cross-sectional view of a fifth exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, a metallic mask layer, a dielectric masklayer, a first organic planarizing layer (OPL), a first antireflectivecoating (ARC) layer, and a photoresist layer and lithographic patterningof the photoresist layer according to a fifth embodiment of the presentdisclosure.

FIG. 28 is a vertical cross-sectional view of a sixth exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, a mask layer, a first organic planarizinglayer (OPL), a first antireflective coating (ARC) layer, and aphotoresist layer and lithographic patterning of the photoresist layeraccording to a sixth embodiment of the present disclosure.

FIG. 29 is a vertical cross-sectional view of a seventh exemplarystructure after deposition of an underlying material layer, and optionaldielectric material layer, at least one mask layer, a first organicplanarizing layer (OPL), a first antireflective coating (ARC) layer, andapplication and patterning of a primary photoresist layer, andapplication and patterning of a secondary photoresist layer according toa seventh embodiment of the present disclosure.

DETAILED DESCRIPTION

As stated above, the present disclosure relates to an image transferprocess employing a hard mask layer to memorize a composite pattern andstructures for effecting the same, which are now described in detailwith accompanying figures. It is noted that like reference numeralsrefer to like elements across different embodiments. The drawings arenot necessarily drawn to scale.

FIG. 1 is a vertical cross-sectional view of a first exemplary structureafter deposition of an underlying material layer, and optionaldielectric material layer, a dielectric mask layer, a metallic masklayer, a first organic planarizing layer (OPL), a first antireflectivecoating (ARC) layer, and mandrel structures according to a firstembodiment of the present disclosure.

Referring to FIG. 1, a first exemplary structure according to a firstembodiment of the present disclosure includes a substrate 10 and amaterial stack formed thereupon. The substrate 10 can include asemiconductor substrate having semiconductor devices (not shown)therein. The semiconductor devices can include, for example, fieldeffect transistors, junction transistors, diodes, resistors, capacitors,inductors, or any other semiconductor device known in the art. Thesubstrate 10 may, or may not, include contact-level dielectric materiallayers (not shown) and/or interconnect level dielectric material layers(not shown) as well as embedded contact via structures (not shown)and/or embedded wiring level metal interconnect structures. Alternately,the topmost portion of the substrate 10 can include a semiconductormaterial such as single crystalline silicon.

An underlying material layer 20L can be formed on the substrate 10. Theunderlying material layer 20L can be a conductive material layer, aplurality of conductive material layers, a single dielectric materiallayer, a plurality of dielectric material layers, or a stack of at leastone dielectric material layer and a conductive material layer. Forexample, the underlying material layer 20L can be a stack of gate levellayers, a wiring-level dielectric material layer, a contact-leveldielectric material layer, a conductive material layer such as a metallayer or a doped semiconductor layer. Exemplary materials that can beincluded in the underlying material layer include, but are not limitedto, gate dielectric materials known in the art, gate conductor materialsknown in the art, doped semiconductor materials, and conductive metallicmaterials, silicon oxide, silicon nitride, silicon oxynitride,organosilicate glass, and stacks thereof. The underlying material layer20L can be deposited, for example, by chemical vapor deposition (CVD),spin coating, or by any other deposition method known in the art. Thethickness of the underlying material layer 20L can be from 10 nm to2,000 nm, although lesser and greater thicknesses can also be employed.In one embodiment, the underlying material layer 20L can be a stack of agate dielectric layer and a gate conductor layer.

An optional dielectric material layer 30L can be optionally deposited onthe top surface of the underlying material layer 20L. The optionaldielectric material layer 30L can be, for example, a silicon nitridelayer or a silicon oxide layer. If the optional dielectric materiallayer 30L includes silicon nitride or silicon oxide, the optionaldielectric material layer 30L can be deposited by a chemical vapordeposition (CVD). The thickness of the optional dielectric materiallayer 30L can be from 30 nm to 300 nm, although lesser and greaterthicknesses can also be employed. In one embodiment, the underlyingmaterial layer 20L can be a stack of gate dielectric layer and a gateconductor layer, and the optional dielectric material layer 30L can be agate cap dielectric layer including silicon nitride or silicon oxide.

At least one mask layer 45L is subsequently deposited on the optionaldielectric material layer 30L or the underlying material layer 20L (ifan optional dielectric material layer is not present). The at least onemask layer 45L can include at least one of a dielectric material and ametallic material. The at least one mask layer 45L can be a stack, frombottom to top, of a dielectric mask layer 40L and a metallic mask layer50L. Alternately, the at least one mask layer 45L can be a stack, frombottom to top, of a metallic mask layer 50L and a dielectric mask layer40L. Yet alternately, the at least one mask layer 45L can be a singlelayer of a dielectric mask layer 40L. Still alternately, the at leastone mask layer 45L can be a single layer of a metallic mask layer 50L.

The dielectric mask layer 40L includes a dielectric material, which canbe silicon oxide, silicon nitride, silicon oxynitride, a dielectricmetal oxide such as HfO₂, LaO₂, or TiO₂, or a combination thereof. Thedielectric mask layer 40L can be deposited, for example, by chemicalvapor deposition (CVD), physical vapor deposition (PVD), or acombination thereof. The thickness of the dielectric mask layer 40L canbe from 10 nm to 100 nm, although lesser and greater thicknesses canalso be employed.

If the dielectric mask layer 40L includes silicon oxide, the dielectricmask layer 40L can be deposited by a chemical vapor deposition (CVD)using tetraethylorthosilicate (TEOS) as a precursor material. Siliconoxide derived from TEOS, commonly referred to as TEOS oxide, can bedeposited by low pressure chemical vapor deposition (LPCVD) or plasmaenhanced chemical vapor deposition (PECVD).

A metallic mask layer 50L is deposited on the dielectric mask layer 40L.The metallic mask layer 50L includes a conductive material. Exemplaryconductive materials that can be employed for the metallic mask layer50L include, but are not limited to, TiN, TaN, WN, TiC, TaC, WC, Ti, Ta,W, and combinations thereof. For example, the metallic mask layer 50Lcan be a TiN layer. The metallic mask layer 50L can be deposited, forexample, by physical vapor deposition (PVD), chemical vapor deposition(CVD), or a combination thereof. The thickness of the metallic masklayer 50L can be from 10 nm to 100 nm, although lesser and greaterthicknesses can also be employed.

A first organic planarizing layer (OPL) 60L is deposited on the topsurface of the at least one mask layer 45L, which can be the top surfaceof the metallic mask layer 50L. The first OPL 60L includes anon-photosensitive organic polymer including carbon, hydrogen, oxygen,and optionally fluorine. For example, the first OPL 60L can includehydrocarbons and/or hydrofluorocarbons. The first OPL 60L can be formed,for example, by spin coating. The thickness of the first OPL 60L can befrom 30 nm to 300 nm, although lesser and greater thicknesses can alsobe employed.

A first antireflective coating (ARC) layer 62L is deposited on the firstOPL 60L. The antireflective coating (ARC) layer is herein referred to asthe first antireflective coating (ARC) layer 62L. The first ARC layer62L can include a hydrocarbon based material having a different materialcomposition than the first OPL 60L. In one embodiment, the first ARClayer 62L comprises silicon at an atomic concentration from 1% to 50%.In another embodiment, the first ARC layer 62L comprises a refractorymetal at an atomic concentration from 1% to 50%. The first ARC layer 62Lcontrols reflectivity of the surface (i.e., the surface of the metallicmask layer 50L) over which the first OPL 60L is patterned by reducingstanding waves and optical notching. The thickness of the first ARClayer 62L may be from 10 nm to 150 nm, and typically from 20 nm to 80nm, although lesser and greater thicknesses are explicitly contemplatedherein. The first ARC layer 62L can be applied, for example, by spincoating.

A mandrel material layer (not shown) is deposited on the first ARC layer62L. The mandrel material layer can include a photoresist, an amorphouscarbon layer, or a material that can be removed selective to thematerial of a conformal material layer to be subsequently deposited. Themandrel material layer is deposited as a blanket layer (unpatternedlayer), for example, by chemical vapor deposition (CVD) or spin coating.The thickness of the mandrel material layer can be from 30 nm to 300 nm,although lesser and greater thicknesses can also be employed.

In one embodiment, the mandrel material layer is a photoresist layerthat can be directly patterned by lithographic exposure and development.The mandrel material layer is patterned by lithographic means, i.e.,exposure and development, to form mandrel structures 70. Thelithographic pattern may be a pattern of a periodic array, or may be anirregular pattern. In one embodiment, the lithographic pattern is apattern of a regular periodic array. The lithographic pattern maycontain an array of lines and spaces, or may contain a pattern of viaholes in a matrix of the mandrel material layer, or may contain apattern of isolated structures separated from one another by acontiguous cavity that laterally surrounds each isolated structure,i.e., each mandrel structure 70. Each of the mandrel structures 70 maybe separated from one another as in the case of a lithographic patterncontaining an array of lines and spaces, or may be adjoined among oneanother as in the case of a lithographic pattern containing an array ofvia holes.

In case the pattern in the mandrel structures 70 comprises a periodicone dimensional array, the pitch of the pattern in the mandrelstructures 70 is a lithographic dimension, which is herein referred toas a lithographic pitch p. If the pattern in the mandrel structures 70is a pattern of lines and spaces, the lithographic pitch p is thelateral dimension of a unit pattern comprising one line and one space.If the pattern in the mandrel structures 70 is a pattern of via holes ina matrix of a contiguous mandrel structure 70, the lithographic pitch isthe lateral dimension of a unit pattern comprising at least one viahole. In addition to having periodicity in one direction at thelithographic pitch p, the pattern in the mandrel structures 70 may haveanother periodicity in another direction. Optionally, overexposure orunderexposure may be employed so that the width of each pattern betweena neighboring pair of the mandrel structures 70 is less than one half ofthe lithographic pitch p.

The lithographic pitch p is a lithographic dimension, i.e., a dimensionthat may be formed by lithographic means. The lithographic pitch p isthe same as, or greater than, the minimum lithographic pitch that may beobtained by commercially available lithography tools. For example, ifArF lithography employing 193 nm wavelength light is used, thelithographic pitch p is the same as, or greater than 80 nm, which is thelithographic minimum pitch.

In other embodiments, the mandrel material layer includes amorphouscarbon or other non-photosensitive material. In such embodiments, aphotoresist (not shown) can be applied over the mandrel material and islithographically patterned into shapes including multiple parallellines. In one embodiment, the multiple parallel lines can have the samewidth and the same pitch. The pitch of the multiple parallel lines is alithographic pitch, i.e., a pitch that can be printed by a singlelithographic exposure employing a commercially available lithographytool and photoresist. A minimum lithographic pitch is herein referred toas a critical pitch, and a pitch that is less than the critical pitch isherein referred to as a sublithographic pitch. The pattern in thephotoresist is transferred into the mandrel material layer to patternthe mandrel material layer into mandrel structures 70. In the caseamorphous carbon or even amorphous silicon is employed as the mandrelmaterial, the first OPL layer 60 can be replaced by a organic layer thathas degas temperature higher than the mandrel deposition temperature. Inone embodiment, OPL layer 60 can be replaced by amorphous carbonmaterial through CVD deposition.

In one embodiment, the mandrel structures 70 can have parallelsidewalls. The parallel sidewalls of the mandrel structures 70 mayvertically coincide with parallel sidewalls of the patternedphotoresist, or may be laterally recessed inward (so that the mandrelstructures 70 have lesser widths than the widths of the patternedphotoresist). In one embodiment, the mandrel structures 70 have alithographic pitch in one direction, which is a horizontal directionperpendicular to the parallel sidewalls of the mandrel structures 70.

Referring to FIG. 2, a conformal material layer 72L is deposited on themandrel structures 70 and the exposed top surface of the first ARC layer62L. The conformal material layer 72L is deposited employing a conformaldeposition method such as molecular layer deposition (MLD), in whichmultiple reactants are alternately provided in a process chamber todeposit the conformal material layer. In MLD, the deposition of thematerial of the conformal material layer 72L occurs one molecular layerat a time. The dielectric material of the conformal material layer 72Lcan include, but is not limited to, silicon oxide, silicon nitride, or acombination thereof. The temperature of the deposition process ismaintained below the decomposition temperature of the material of themandrel structures 70.

In one embodiment, the mandrel structures 70 include a photoresist, andthe conformal material layer includes silicon dioxide. Silicon oxide canbe deposited at room temperature employing a molecular layer depositionprocess.

In another embodiment, the mandrel structures 70 include amorphouscarbon, and the conformal material layer includes silicon oxide orsilicon nitride. Silicon nitride can be deposited at a temperature about400° C. employing a molecular layer deposition process.

Any other combination of materials for the mandrel structures 70 and theconformal material layer 72L can be employed provided that the materialof the mandrel structures 70 can withstand the deposition process forthe conformal material layer, that the conformal material layer 72L canbe conformally deposited on the sidewalls of the mandrel structures 70,and that the mandrels can be removed selective to the material of theconformal material layer 72L and the first ARC layer 62L.

Referring to FIG. 3, an anisotropic etch is performed to removehorizontal portions of the conformal material layer 72L. The verticalportions of the conformal material layer 72L that remains on thevertical sidewalls of the mandrels constitute a set of spacer structures72, which include the same dielectric material as the conformal materiallayer 72L. Thus, the remaining disjoined portions of the conformalmaterial layer 72L are the set of spacer structures 72. In oneembodiment, the mandrel structures 70 can be patterned line structureshaving parallel vertical sidewalls. Each spacer structure 72 has a samewidth, and laterally surrounds and contacts a mandrel structure 70. Eachof said spacer structures 72 can have a same lateral width, which can bethe same as the thickness of the conformal material layer 72 asdeposited.

The pattern in the spacer structures 72 is herein referred to as a firstpattern. The spacer structures 72 collectively constitute a patternedstructure including the first pattern. In one embodiment, the spacerstructures can have a pitch that is one half of the lithographic pitchp. In this case, the patterned structure can include spacer structures72 having a sublithographic pitch.

Each of the spacer structures 72 can laterally contact and laterallysurround one of the mandrel structures 70. In one embodiment, themandrel structures 70 can include a photoresist material. In anotherembodiment, the mandrel structures 70 can include amorphous carbon.

Referring to FIG. 4, the mandrel structures 70 are removed by anotheretch, which can be an anisotropic etch or an isotropic etch, that isselective to the materials of the spacer structures 72 and the first ARClayer 62L.

In one embodiment, the first pattern may include two patterned linestructures within a lithographic pitch p. If the lithographic pitch is aminimum lithographic pitch that can be lithographically printed, thewidth of the spacer structures 72 can be a sublithographic width, i.e.,a width that is less than the minimum width of a patterned structurethat can be formed by single exposure and development.

The first exemplary structure illustrated in FIG. 4 is a lithographicstructure, which includes the underlying material layer 20L located onthe substrate 10; at least one mask layer 45L including at least one ofa dielectric material and a metallic material and located over theunderlying material layer 20L; the first organic planarizing layer (OPL)60L located over the at least one mask layer 45L; the firstantireflective coating (ARC) layer 62L located on the first OPL 60L; andthe patterned structure of the spacer structures 72 located over thefirst ARC layer 62L. In one embodiment, the patterned structure has apattern of a plurality of parallel lines, i.e., the first pattern can bea pattern of a plurality of parallel lines.

Each of the at least one mask layer 45L can be a blanket layer having asame thickness throughout, i.e., an unpatterned material layer. In oneembodiment, the at least one mask layer 45L can be a stack, from bottomto top, of the dielectric mask layer 40L and the metallic mask layer50L. In another embodiment, the at least one mask layer 45L can be astack, from bottom to top, of a metallic mask layer 50L and a dielectricmask layer 40L. In yet another embodiment, the at least one mask layer45L can be a single layer of a dielectric mask layer 40L. In stillanother embodiment, the at least one mask layer 45L can be a singlelayer of a metallic mask layer 50L.

Referring to FIG. 5, the first pattern in the set of spacer structures72 is transferred into the first ARC layer 62L by an anisotropic etch.The set of spacer structures 72 is employed as an etch mask during thetransfer of the first pattern into the first ARC layer 62L. The firstARC layer 62L becomes a patterned first ARC layer 62, which includes aplurality of ARC portions that replicate the first pattern.

Referring to FIG. 6, the first pattern is transferred into the first OPL60L by another anisotropic etch. The anisotropic etch employs the set ofspacer structures 72 and/or the patterned first ARC layer 62 as the etchmask. For example, the set of spacer structures 72 can be consumedduring an initial portion of the anisotropic and consumed before the endof the anisotropic etch, and the patterned first ARC layer 62 can beemployed as the etch mask during a latter portion of the anisotropicetch. Alternately, the set of spacer structures 72 can be employed asthe etch mask layer throughout the anisotropic etch, and removedselective to the material of the first OPL 60L after the anisotropicetch. The first OPL 60L becomes a patterned first OPL 60 by theanisotropic etch, which includes a plurality of OPL portions. Thepatterned first OPL 60 includes the first pattern.

Referring to FIG. 7, the first pattern into at least an upper portion ofthe at least one mask layer 45L by an anisotropic etch. The patternedfirst ARC layer 62 can be employed as the etch mask during theanisotropic etch. The first pattern is formed in one of the at least onemask layer 45L. A patterned mask layer including the first pattern isthus formed. If the at least one mask layer 45L includes a stack ofmultiple mask layers, the patterned mask layer can be a patterned layerformed from the topmost layer among the multiple mask layers. If the atleast one mask layer 45L includes a single mask layer, the patternedmask layer is a patterned layer of the single mask layer. The patternedfirst ARC layer 62 can be consumed during the anisotropic etch, or canbe removed after the anisotropic etch. If the patterned first ARC layer62 is consumed before the anisotropic etch is completed, the patternedfirst OPL 60 can be employed as the etch mask during the remainder ofthe anisotropic etch. At least partially patterned mask layer 45 is thusformed.

For example, if the at least one mask layer 45L includes a verticalstack, from bottom to top, of the dielectric mask layer 40L and themetallic mask layer 50L, the first pattern is transferred into themetallic mask layer 50L. The patterned mask layer is a patternedmetallic mask layer 50 in this case. The at least partially patternedmask layer 45 includes a stack, from bottom to top, of the dielectricmask layer 40L and the patterned metallic mask layer 50.

If the at least one mask layer 45L includes a vertical stack, frombottom to top, of a metallic mask layer 50L and a dielectric mask layer40L, the first pattern is transferred into the dielectric mask layer40L. The patterned mask layer is a patterned dielectric mask layer (notshown) in this case. The at least partially patterned mask layer 45includes a stack, from bottom to top, of the metallic mask layer 50L andthe patterned dielectric mask layer.

If the at least one mask layer 45L includes a single metallic mask layer50L, the first pattern is transferred into the metallic mask layer 50L.The patterned mask layer is a patterned metallic mask layer 50 in thiscase. The at least partially patterned mask layer 45 consists of thepatterned metallic mask layer 50.

If the at least one mask layer 45L includes a single dielectric masklayer 40L, the first pattern is transferred into the dielectric masklayer 40L. The patterned mask layer is a patterned dielectric mask layerin this case. The at least partially patterned mask layer 45 consists ofthe patterned dielectric mask layer.

The anisotropic etch can be a reactive ion etch employing a plasma of atleast one fluorocarbon gas such as CF₄, CHF₃, and C₄F₈. Argon ornitrogen can also be added to the plasma. In general, the chemistry ofthe anisotropic etch for etching the metallic mask layer 50L is selectedto simultaneously etch the material of the metallic mask layer 50L andthe patterned first ARC layer 62. Thus, the pattern in the first OPL 60is transferred into the metallic mask layer 50L to form a pattern oftrenches therein, and the top surface of the dielectric mask layer 40Lis exposed at the bottom of the trenches.

Because the at least one mask layer 45L does not include any organicmaterial and includes only non-organic material(s), line edge roughnessand line width roughness in the transferred first pattern in the atleast partially patterned mask layer 45 is significantly reducedrelative to any process that transfers a similar pattern into an organicmaterial layer such as an amorphous carbon layer.

Referring to FIG. 8, the patterned first OPL 60 is removed selective tothe patterned mask layer, e.g., the patterned metallic mask layer 50.The patterned first OPL 60 can be removed selective to the patternedmetallic mask layer 50 and the dielectric mask layer 40L, for example,by ashing.

Referring to FIG. 9, a second OPL 160L, a second ARC layer 162L, and afirst photoresist layer 170 are sequentially applied over the patternedmask layer, e.g., the patterned metallic mask layer 50. The firstphotoresist layer 170 is lithographically patterned with a secondpattern. The second pattern includes at least one blocking area, whichis the area of the remaining portions of the first photoresist layer 170after lithographic exposure and development. At least one opening isformed within the first photoresist layer. The area of the at least oneopening is the complement of the at least one blocking area.

The at least one blocking area has lithographic dimensions, i.e.,dimensions that are not less than the minimum lithographic dimension. Inone embodiment, the first photoresist layer 170 can include amid-ultraviolet (MUV) photoresist material or a deep-ultraviolet (DUV)photoresist material.

The first exemplary structure illustrated in FIG. 9 is a lithographicstructure that includes: the underlying material layer 20L located onthe substrate 10; a patterned mask layer including at least one of adielectric material and a metallic material and located over theunderlying material layer 20L; the second OPL 160L located over thepatterned mask layer; the second ARC layer 162L located on the secondOPL 160L; and the first photoresist layer 170 located over the secondARC layer 162L and including at least one opening therein.

In one embodiment, the patterned mask layer can be the patternedmetallic mask layer 50, and a dielectric mask layer 40L can be presentunderneath the patterned metallic mask layer 50. The dielectric masklayer 40L can be located over the underlying material layer 20L, and thepatterned mask layer includes a metallic material, and is located on atop surface of the dielectric mask layer 40L.

In another embodiment, the patterned mask layer can be a patterneddielectric mask layer (not shown), and a metallic mask layer can bepresent underneath the patterned dielectric mask layer. The metallicmask layer can be located over the underlying material layer 20L. Thepatterned mask layer includes a dielectric material, and is located on atop surface of the metallic mask layer.

In yet another embodiment, the patterned mask layer can be a patternedmetallic mask layer 50 that is in direct contact with the optionaldielectric material layer 30L or the underlying material layer 20L. Instill another embodiment, the patterned mask layer can be a patterneddielectric mask layer that is in direct contact with the optionaldielectric material layer 30L or the underlying material layer 20L.

In one embodiment, the patterned mask layer such as the patternedmetallic mask layer 50 can include a periodic pattern of a plurality ofparallel line structures that are laterally spaced from one another,i.e., the plurality of portions of the metallic material that constitutethe patterned metallic mask layer 50. In one embodiment, the periodicpattern can have a lithographic minimum pitch. In another embodiment,the periodic pattern can have a sublithographic pitch.

In one embodiment, the underlying material layer 20L can include aconductive material layer, and the optional dielectric material layer30L can have a different composition than the patterned mask layer. Theconductive material layer can include at least one of a dopedpolycrystalline semiconductor material and a metal layer, and theoptional dielectric material layer 30L can include silicon nitride.

An overlying structure including the second pattern (e.g., the firstphotoresist layer 170) is present over the patterned mask layer, e.g.,the patterned metallic mask layer 50. The second pattern includes the atleast one blocking area.

Referring to FIG. 10, the second pattern is transferred down to an upperportion of the second OPL 160L. The second ARC layer 162L and an upperportion of the second OPL 160L are etched in an anisotropic etch thatemploys the first photoresist layer 170 as an etch mask. The firstphotoresist layer 170 can be consumed during the etching of the secondOPL 160L.

An overlying structure including the second pattern (e.g., the stack ofthe upper portion of the second OPL 160L and the second ARC layer 162L)is present over the patterned mask layer, e.g., the patterned metallicmask layer 50.

Referring to FIG. 11, the second ARC layer 162L can be removed duringthe etching of the second OPL 160L or in a separate etch step.

Referring to FIG. 12, physically exposed portions of the patterned masklayer, e.g., the patterned metallic mask layer 50, can be removedselective to the material of the layer contacting the bottom surface ofthe patterned mask layer, e.g., the dielectric mask layer 40L. Theportions of the patterned mask layer that do not underlie the blockingarea are removed by etching the portions of the patterned mask layerfrom within an area of the at least one opening, i.e., within the areaof the second region R2, which is the area of the complement of thesecond pattern. The remaining portions of the patterned mask layerinclude a composite pattern that is an intersection of the first patternand the second pattern.

Referring to FIG. 13, the second OPL 160L can be removed, for example,by ashing. The remaining portions of the second OPL 160L can be removedselective to the remaining portions of the patterned mask layer.

The patterned mask layer can include a plurality of patterned maskportions that is present over a first region R1 of the underlyingmaterial layer 20L, and the patterned mask layer is not present over asecond region R2 of the underlying material layer. The plurality ofpatterned mask portions can be a periodic array of parallel linestructures having a pitch that is not greater than a minimumlithographic pitch. In one embodiment, the second region R2 can have awidth that is greater than twice the pitch p (See FIG. 3).

Because the at least partially patterned mask layer 45 does not includeany organic material and includes only non-organic material(s), the lineedge roughness or line width roughness of the sidewalls of the at leastpartially patterned mask layer 45 does not increase during the removalof the second OPL 160L.

Referring to FIG. 14, a second photoresist layer can be optionallyapplied over the remaining portions of the patterned mask layer, e.g.,the patterned metallic mask layer 50. The second photoresist layer canbe applied, for example, by spin coating. The second photoresist layercan be lithographically patterned by lithographic exposure anddevelopment to form at least one photoresist block portion 77 having anadditional pattern, which is herein referred to as a third pattern.

The third pattern can be any lithographic pattern. The third pattern ispresent in the area of the at least one photoresist block portion 77. Inone embodiment, the third pattern can be present within the area of thesecond region R2. In one embodiment, the third pattern can defineregions having a lateral dimension greater than the pitch p (See FIG.3).

In one embodiment, a trilayer material stack including an organicplanarizing layer, a silicon-containing anti-reflective coating (ARC)layer, and a photoresist layer can be employed instead of the secondphotoresist layer. The organic planarizing layer can include the samematerial as the first OPL 60 or as the second OPL 160, and can bedeposited such that a planar topmost surface of the organic planarizinglayer is formed above the topmost surfaces of the patterned metallicmask layer 50. The silicon-containing ARC layer can include anysilicon-containing ARC material known in the art. The photoresist layercan be patterned with the third pattern. After lithographic exposure anddevelopment of the photoresist layer, physically exposed portions of thesilicon-containing ARC layer can be removed by an etch employing theremaining portions of the photoresist layer as an etch mask.Subsequently, physically exposed portions of the organic planarizinglayer are removed by another etch, which can employ remaining portionsof the photoresist layer and/or the silicon-containing ARC layer as anetch mask. At least one organic planarizing material portion (andoptionally at least one silicon-containing ARC material portionoverlying the at least one organic planarizing material portion) can bepresent in the area of the at least one photoresist block portion 77,and subsequently serve the function of the at least one photoresistblock portion 77 in this embodiment.

Referring to FIG. 15, a pattern derived from the composite pattern ofthe intersection of the first pattern and the second pattern and fromthe third pattern is transferred into the rest of the at least partiallypatterned mask layer 45 and the optional dielectric material layer 30L.The derived pattern can be a union of the third pattern and a compositepattern that is the intersection of the first pattern and the secondpattern. For example, the derived pattern can be transferred into thedielectric mask layer 40L and the optional dielectric material layer30L. The remaining portions of the dielectric mask layer 40L constitutea patterned dielectric mask layer 40, and the remaining portions of theoptional dielectric material layer 30L constitute an optional patterneddielectric material layer.

Because the at least partially patterned mask layer 45 does not includeany organic material and includes only non-organic material(s), the lineedge roughness or line width roughness of the sidewalls of the at leastpartially patterned mask layer 45 does not increase significantly duringthe pattern transfer etch that transfers the derived pattern into theoptional dielectric material layer 30L.

Referring to FIG. 16, the derived pattern is transferred into an upperportion of the underlying material layer 20L. The transfer of thederived pattern into the underlying material layer 20 can be effected byetching the underlying material layer 20L employing the remainingportions of the patterned mask layer, e.g., the patterned metallicmaterial layer 50, and the at least one photoresist block portion 77 asan etch mask.

Optionally, the patterned mask layer, e.g., the patterned metallic masklayer 50, can be removed once the derived pattern is transferred intoany layer between the patterned mask layer and the underlying materiallayer 20L. For example, the patterned metallic mask layer 50 can beremoved after the derived pattern is transferred into the patterneddielectric mask layer 40 and/or the optional patterned dielectricmaterial layer 30.

In one embodiment, the patterned mask layer, e.g., the patternedmetallic mask layer 50, can be consumed during the anisotropic etch thattransfers the derived pattern into the dielectric mask layer 40L, theoptional dielectric material layer 30L, and/or the underlying materiallayer 20L. In another embodiment, the removal of the patterned masklayer, e.g., the patterned metallic mask layer 50, can be performed byan etch process that removes the material of the patterned mask layerselective to physically exposed material underneath the patterned masklayer. In one embodiment, the remaining portions of the patterned masklayer, e.g., the patterned metallic mask layer 50, can be removedselective to the underlying material layer 20L after the transfer of thederived pattern. The at least one photoresist block portion 77 can beconsumed during the transfer of the derived pattern, or alternately, canbe removed, for example, by ashing.

Referring to FIG. 17, the derived pattern is transferred to the bottomof the underlying material layer 20L. All materials of the at least onemask layer 45L are removed. For example, the patterned dielectric masklayer 40 is removed selective to the materials of the optional patterneddielectric material layer 30 and the patterned underlying material layer20.

Referring to FIG. 18, a second exemplary structure according to a secondembodiment of the present disclosure is derived from the first exemplarystructure of FIG. 1 by altering the at least one mask layer 45L.Specifically, a vertical stack, from bottom to top, of the metallic masklayer 50L and the dielectric mask layer 40L is employed for the at leastone mask layer 45L. The metallic mask layer 50L of the second embodimentcan have the same composition and thickness as in the first embodiment,and can be formed by the same method as in the first embodiment. Thedielectric mask layer 40L of the second embodiment can have the samecomposition and thickness as in the first embodiment, and can be formedby the same method as in the first embodiment.

Referring to FIG. 19, the processing steps of FIGS. 2-6 can beperformed. Subsequently, the first pattern into at least an upperportion of the at least one mask layer 45L by an anisotropic etch. Thepatterned first ARC layer 62 can be employed as the etch mask during theanisotropic etch. The first pattern is formed in one of the at least onemask layer 45L. A patterned mask layer including the first pattern isthus formed. The patterned first ARC layer 62 can be consumed during theanisotropic etch, or can be removed after the anisotropic etch. If thepatterned first ARC layer 62 is consumed before the anisotropic etch iscompleted, the patterned first OPL 60 can be employed as the etch maskduring the remainder of the anisotropic etch. At least partiallypatterned mask layer 45 is thus formed.

In this embodiment, the first pattern is transferred into the dielectricmask layer 40L. The patterned mask layer is a patterned dielectric masklayer 40. The at least partially patterned mask layer 45 includes astack, from bottom to top, of the metallic mask layer 50L and thepatterned dielectric mask layer 45.

The chemistry of the anisotropic etch for etching the dielectric masklayer 40L is selected to simultaneously etch the material of thedielectric mask layer 40L and the patterned first ARC layer 62. Thus,the pattern in the first OPL 60 is transferred into the dielectric masklayer 40L to form a pattern of trenches therein, and the top surface ofthe metallic mask layer 50L is exposed at the bottom of the trenches.

Subsequently, the patterned first OPL 60 is removed selective to thepatterned mask layer, e.g., the patterned dielectric mask layer 40. Thepatterned first OPL 60 can be removed selective to the patterneddielectric mask layer 40 and the metallic mask layer 50L, for example,by ashing.

Referring to FIG. 20, processing steps of FIGS. 9-11 are performed.Subsequently, physically exposed portions of the patterned mask layer,e.g., the patterned dielectric mask layer 40, can be removed selectiveto the material of the layer contacting the bottom surface of thepatterned mask layer, e.g., the metallic mask layer 50L. The portions ofthe patterned mask layer that do not underlie the blocking area areremoved by etching the portions of the patterned mask layer from withinan area of the at least one opening, i.e., within the area of the secondregion R2, which is the area of the complement of the second pattern.The remaining portions of the patterned mask layer include a compositepattern that is an intersection of the first pattern and the secondpattern.

The second OPL 160L can then be removed, for example, by ashing. Theremaining portions of the second OPL 160L can be removed selective tothe remaining portions of the patterned mask layer.

The patterned mask layer, i.e., the patterned dielectric mask layer 40,can include a plurality of patterned mask portions that is present overa first region R1 of the underlying material layer 20L, and thepatterned mask layer is not present over a second region R2 of theunderlying material layer. The plurality of patterned mask portions canbe a periodic array of parallel line structures having a pitch that isnot greater than a minimum lithographic pitch. In one embodiment, thesecond region R2 can have a width that is greater than twice the pitch p(See FIG. 3).

Referring to FIG. 21, the processing step of FIG. 14 is performed.Subsequently, a pattern derived from the composite pattern of theintersection of the first pattern and the second pattern and from thethird pattern is transferred into the rest of the at least partiallypatterned mask layer 45 and the optional dielectric material layer 30L.The derived pattern can be a union of the third pattern and a compositepattern that is the intersection of the first pattern and the secondpattern. For example, the derived pattern can be transferred into themetallic mask layer 50L and the optional dielectric material layer 30L.The remaining portions of the metallic mask layer 50L constitute apatterned dielectric mask layer 50, and the remaining portions of theoptional dielectric material layer 30L constitute an optional patterneddielectric material layer.

Subsequently, the derived pattern is transferred into an upper portionof the underlying material layer 20L. The transfer of the derivedpattern into the underlying material layer 20 can be effected by etchingthe underlying material layer 20L employing the remaining portions ofthe patterned mask layer, e.g., the patterned dielectric material layer40, and the at least one photoresist block portion 77 (See FIG. 15) asan etch mask.

Optionally, the patterned mask layer, e.g., the patterned dielectricmask layer 40, can be removed once the derived pattern is transferredinto any layer between the patterned mask layer and the underlyingmaterial layer 20L. For example, the patterned dielectric mask layer 40can be removed after the derived pattern is transferred into thepatterned metallic mask layer 50 and/or the optional patterneddielectric material layer 30.

In one embodiment, the patterned mask layer, e.g., the patterneddielectric mask layer 40, can be consumed during the anisotropic etchthat transfers the derived pattern into the metallic mask layer 50L, theoptional dielectric material layer 30L, and/or the underlying materiallayer 20L. In another embodiment, the removal of the patterned masklayer, e.g., the patterned dielectric mask layer 40, can be performed byan etch process that removes the material of the patterned mask layerselective to physically exposed material underneath the patterned masklayer. In one embodiment, the remaining portions of the patterned masklayer, e.g., the patterned dielectric mask layer 40, can be removedselective to the underlying material layer 20L after the transfer of thederived pattern. The at least one photoresist block portion 77 can beconsumed during the transfer of the derived pattern, or alternately, canbe removed, for example, by ashing.

The anisotropic etch can be continued to provide the same structure asthe first exemplary structure shown in FIG. 17.

Referring to FIG. 22, a third exemplary structure according to a thirdembodiment of the present disclosure is derived from the first exemplarystructure of FIG. 1 by altering the at least one mask layer 45L.Specifically, a homogeneous mask layer 145L including a metallicmaterial or a dielectric material can be employed for the at least onemask layer 45L. The homogeneous mask layer 145L can have a samecomposition throughout. The homogeneous mask layer 145L can have thesame composition as the dielectric mask layer 40L of the firstembodiment, or as the metallic mask layer 50L of the first embodiment.The thickness of the homogeneous mask layer 145L can be from 30 nm to600 nm, although lesser and greater thicknesses can also be employed.The homogeneous mask layer 145L can be formed employing methods forforming the dielectric mask layer 40L or employing methods for formingthe metallic mask layer 50L.

Referring to FIG. 23, the processing steps of FIGS. 2-6 can beperformed. Subsequently, the first pattern into at least an upperportion of the homogeneous mask layer 145L by an anisotropic etch. Thepatterned first ARC layer 62 can be employed as the etch mask during theanisotropic etch. The first pattern is formed in one of the homogeneousmask layer 145L. A patterned mask layer including the first pattern isthus formed. The patterned first ARC layer 62 can be consumed during theanisotropic etch, or can be removed after the anisotropic etch. If thepatterned first ARC layer 62 is consumed before the anisotropic etch iscompleted, the patterned first OPL 60 can be employed as the etch maskduring the remainder of the anisotropic etch. A patterned homogeneousmask layer 145 is thus formed.

In this embodiment, the first pattern is transferred into thehomogeneous mask layer 145L. The patterned mask layer is a patternedhomogeneous mask layer 145.

The chemistry of the anisotropic etch for etching the dielectric masklayer 40L is selected to simultaneously etch the material of thehomogeneous mask layer 145L and the patterned first ARC layer 62. Thus,the pattern in the first OPL 60 is transferred into the homogeneous masklayer 145L to form a pattern of trenches therein, and the top surface ofthe optional dielectric material layer 30L is exposed at the bottom ofthe trenches.

Subsequently, the patterned first OPL 60 is removed selective to thepatterned mask layer, e.g., the patterned homogeneous mask layer 145.The patterned first OPL 60 can be removed selective to the patternedhomogeneous mask layer 145 and the optional dielectric material layer30L, for example, by ashing.

Referring to FIG. 24, processing steps of FIGS. 9-11 are performed.Subsequently, physically exposed portions of the patterned mask layer,e.g., the patterned homogeneous mask layer 145, can be removed selectiveto the material of the layer contacting the bottom surface of thepatterned mask layer, e.g., the optional dielectric material layer 30Lor the underlying material layer 20L. The portions of the patterned masklayer that do not underlie the blocking area are removed by etching theportions of the patterned mask layer from within an area of the at leastone opening, i.e., within the area of the second region R2, which is thearea of the complement of the second pattern. The remaining portions ofthe patterned mask layer include a composite pattern that is anintersection of the first pattern and the second pattern.

The second OPL 160L can then be removed, for example, by ashing. Theremaining portions of the second OPL 160L can be removed selective tothe remaining portions of the patterned mask layer.

The patterned mask layer, i.e., the patterned homogeneous mask layer145, can include a plurality of patterned mask portions that is presentover a first region R1 of the underlying material layer 20L, and thepatterned mask layer is not present over a second region R2 of theunderlying material layer. The plurality of patterned mask portions canbe a periodic array of parallel line structures having a pitch that isnot greater than a minimum lithographic pitch. In one embodiment, thesecond region R2 can have a width that is greater than twice the pitch p(See FIG. 3).

Referring to FIG. 25, the processing step of FIG. 14 is performed.Subsequently, a pattern derived from the composite pattern of theintersection of the first pattern and the second pattern and from thethird pattern is transferred into the optional dielectric material layer30L, if present. The derived pattern can be a union of the third patternand a composite pattern that is the intersection of the first patternand the second pattern. The remaining portions of the optionaldielectric material layer 30L constitute an optional patterneddielectric material layer.

Subsequently, the derived pattern is transferred into an upper portionof the underlying material layer 20L. The transfer of the derivedpattern into the underlying material layer 20 can be effected by etchingthe underlying material layer 20L employing the remaining portions ofthe patterned mask layer, e.g., the patterned homogeneous mask layer145, and the at least one photoresist block portion 77 (See FIG. 15) asan etch mask.

Optionally, the patterned mask layer, e.g., the patterned homogeneousmask layer 145, can be removed once the derived pattern is transferredinto any layer between the patterned mask layer and the underlyingmaterial layer 20L. For example, the patterned homogeneous mask layer145 can be removed after the derived pattern is transferred into theoptional patterned dielectric material layer 30.

In one embodiment, the patterned mask layer, e.g., patterned homogeneousmask layer 145, can be consumed during the anisotropic etch thattransfers the derived pattern into the optional dielectric materiallayer 30L and/or the underlying material layer 20L. In anotherembodiment, the removal of the patterned mask layer, e.g., the patternedhomogeneous mask layer 145, can be performed by an etch process thatremoves the material of the patterned mask layer selective to physicallyexposed material underneath the patterned mask layer. In one embodiment,the remaining portions of the patterned mask layer, e.g., the patternedhomogeneous mask layer 145, can be removed selective to the underlyingmaterial layer 20L after the transfer of the derived pattern. The atleast one photoresist block portion 77 can be consumed during thetransfer of the derived pattern, or alternately, can be removed, forexample, by ashing.

The anisotropic etch can be continued to provide the same structure asthe first exemplary structure shown in FIG. 17.

Referring to FIG. 26, a fourth exemplary structure according to a fourthembodiment of the present disclosure can be derived from the firstexemplary structure of FIG. 1 by not forming the mandrel structures 70and by applying and lithographically patterning a photoresist layer toform a patterned photoresist layer 80 including a first pattern. Thepatterned photoresist layer 80 can include a set of photoresist materialportions.

The fourth exemplary structure illustrated in FIG. 26 is a lithographicstructure, which includes the underlying material layer 20L located onthe substrate 10; at least one mask layer 45L including at least one ofa dielectric material and a metallic material and located over theunderlying material layer 20L; the first organic planarizing layer (OPL)60L located over the at least one mask layer 45L; the firstantireflective coating (ARC) layer 62L located on the first OPL 60L; andthe patterned structure of the patterned photoresist layer 80 locatedover the first ARC layer 62L.

In one embodiment, the patterned structure has a pattern of a pluralityof parallel lines. In one embodiment, the patterned structure includes aset of photoresist material portions having a lithographic minimumpitch. The processing step of FIG. 5 can be subsequently performedemploying the patterned photoresist layer 80 as an etch mask.Subsequently, processing steps of FIGS. 6-17 can be performed.

Referring to FIG. 27, a fifth exemplary structure according to a fifthembodiment of the present disclosure can be derived from the secondexemplary structure of FIG. 18 by not forming the mandrel structures 70and by applying and lithographically patterning a photoresist layer toform a patterned photoresist layer 80 including a first pattern. Thepatterned photoresist layer 80 can include a set of photoresist materialportions.

In one embodiment, the patterned structure has a pattern of a pluralityof parallel lines. In one embodiment, the patterned structure includes aset of photoresist material portions having a lithographic minimumpitch. The processing step of FIG. 5 can be subsequently performedemploying the patterned photoresist layer 80 as an etch mask. Processingsteps of the second embodiment can be subsequently performed.

Referring to FIG. 28, a sixth exemplary structure according to a sixthembodiment of the present disclosure can be derived from the secondexemplary structure of FIG. 22 by not forming the mandrel structures 70and by applying and lithographically patterning a photoresist layer toform a patterned photoresist layer 80 including a first pattern. Thepatterned photoresist layer 80 can include a set of photoresist materialportions.

In one embodiment, the patterned structure has a pattern of a pluralityof parallel lines. In one embodiment, the patterned structure includes aset of photoresist material portions having a lithographic minimumpitch. The processing step of FIG. 5 can be subsequently performedemploying the patterned photoresist layer 80 as an etch mask. Processingsteps of the third embodiment can be subsequently performed.

Referring to FIG. 29, a seventh exemplary structure a according to aseventh embodiment of the present disclosure can be derived from any ofthe fourth, fifth, and sixth exemplary structures illustrated in FIGS.26, 27, and 28 by applying and patterning multiple photoresist layersinstead of employing a single photoresist layer. For example, a primaryphotoresist layer 70A can be applied and lithographically patterned, anda secondary photoresist layer 70B can be subsequently applied andlithographically patterned.

The seventh exemplary structure illustrated in FIG. 29 is a lithographicstructure, which includes the underlying material layer 20L located onthe substrate 10; at least one mask layer 45L including at least one ofa dielectric material and a metallic material and located over theunderlying material layer 20L; the first organic planarizing layer (OPL)60L located over the at least one mask layer 45L; the firstantireflective coating (ARC) layer 62L located on the first OPL 60L; andthe patterned structure of the spacer structures 72 located over thefirst ARC layer 62L.

In one embodiment, the patterned structure has a pattern of a pluralityof parallel lines. In one embodiment, the patterned structure includes aset of first photoresist material portions including a first photoresistmaterial (e.g., the primary photoresist layer 70A) and a set of secondphotoresist material portions including a second photoresist materialthat is different from the first photoresist material (e.g., thesecondary photoresist layer 70B). The processing step of FIG. 5 can besubsequently performed employing the patterned photoresist layer 80 asan etch mask. Subsequently, processing steps of FIGS. 6-17 can beperformed.

The various embodiments of the present disclosure enables high fidelitytransfer of the derived pattern including at least the composite patternof the first pattern and the second pattern, and optionally including anadditional pattern (the third pattern). Due to the absence of anyorganic material within the at least one mask layer 45L, the material(s)of the at least one mask layer 45L is/are not prone to increase in lineedge roughness or line width roughness during the transfer of the firstpattern therein, or during the removal of the patterned first OPL 60, orduring the removal of the second OPL 160L, or during the anisotropicetch that transfers the derived pattern into the underlying layers.

While the present disclosure has been particularly shown and describedwith respect to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formsand details may be made without departing from the spirit and scope ofthe present disclosure. It is therefore intended that the presentdisclosure not be limited to the exact forms and details described andillustrated, but fall within the scope of the appended claims.

1. A method of patterning a structure comprising: forming an underlyingmaterial layer on a substrate; forming a stack of two mask layerscomprising a dielectric material and a metallic material, respectively,over said underlying material layer; forming a first pattern in one ofsaid two mask layers, wherein a patterned mask layer including saidfirst pattern is formed by remaining portions of said one of said twomask layers, while another of said two mask layers remains unpatterned;forming an overlying structure including a second pattern over saidpatterned mask layer, wherein said second pattern includes at least oneblocking area; removing portions of said patterned mask layer that donot underlie said blocking area, wherein remaining portions of saidpatterned mask layer include a composite pattern that is an intersectionof said first pattern and said second pattern; applying a photoresistmaterial directly on surfaces of said patterned mask layer and onsurfaces of said another of said two mask layers that remainsunpatterned; patterning said photoresist material to form at least onephotoresist block portion having an additional pattern directly on atopmost surface of said another of said two mask layers; transferring aderived pattern including said composite pattern and a pattern of saidat least one photoresist block portion as component patterns into saidanother of said two mask layers; and transferring said derived patterninto said underlying material layer employing remaining portions of saidanother of said two mask layers as an etch mask.
 2. The method of claim1, further comprising: forming a stack of a first organic planarizinglayer (OPL) and a first antireflective coating (ARC) layer on said atleast one mask layer; and forming a patterned structure including saidfirst pattern over said first ARC layer, wherein said forming of saidfirst pattern in said one of said at least one mask layer comprisestransferring said first pattern into said one of said at least one masklayer.
 3. The method of claim 2, further comprising etching said firstARC layer and said first OPL employing said patterned structure as anetch mask, wherein a patterned first ARC layer and a patterned first OPLare formed.
 4. The method of claim 3, wherein said transferring of saidfirst pattern into said one of said at least one mask layer comprisesetching said one of said at least one mask layer employing saidpatterned first ARC layer as an etch mask.
 5. The method of claim 4,further comprising removing said patterned first OPL selective to saidpatterned mask layer prior to forming said overlying structure.
 6. Themethod of claim 2, wherein said forming of said patterned structurecomprises forming a set of spacer structures.
 7. The method of claim 6,wherein said set of spacer structures is formed by: forming mandrelstructures over said first ARC layer; depositing a conformal materiallayer over said mandrel structures; and anisotropically etching saidconformal material layer, wherein remaining disjoined portions of saidconformal material layer are said set of spacer structures.
 8. Themethod of claim 7, further comprising removing said mandrel structuresselective to said set of spacer structures and said first ARC layer. 9.The method of claim 7, wherein said forming of said mandrel structurescomprise: depositing a mandrel material layer over said first ARC layer;and patterning said mandrel material layer to form said mandrelstructures.
 10. The method of claim 2, wherein said patterned structurecomprises a set of first photoresist material portions comprising afirst photoresist material and a set of second photoresist materialportions comprising a second photoresist material that is different fromsaid first photoresist material.
 11. The method of claim 2, wherein saidforming of said overlying structure comprises forming a stack of asecond OPL, a second ARC layer, and a photoresist layer over saidpatterned mask layer.
 12. The method of claim 11, further comprisinglithographically patterning said photoresist layer with said secondpattern, wherein said second pattern includes at least one opening thatis a complement of said at least one blocking area.
 13. The method ofclaim 12, further comprising etching said second ARC layer and an upperportion of said second OPL employing said photoresist layer as an etchmask.
 14. The method of claim 13, wherein said removing of said portionsof said patterned mask layer that do not underlie said blocking areacomprises etching said portions of said patterned mask layer from withinan area of said at least one opening after said etching of said upperportion of said second OPL.
 15. The method of claim 14, furthercomprising removing remaining portions of said second OPL selective tosaid remaining portions of said patterned mask layer. 16.-17. (canceled)18. The method of claim 1, wherein said transferring of said derivedpattern into said underlying material layer comprises etching saidunderlying material layer employing a combination of said remainingportions of said patterned mask layer and said at least one photoresistblock portion as an etch mask.
 19. The method of claim 1, wherein saidderived pattern is a union of said composite pattern and said additionalpattern.
 20. The method of claim 1, wherein said underlying materiallayer comprises a gate conductor layer.
 21. The method of claim 1,further comprising removing said remaining portions of said patternedmask layer selective to said underlying material layer after saidtransferring of said derived pattern.
 22. The method of claim 1, whereinsaid at lest one mask layer comprises a stack, from bottom to top, of adielectric mask layer and a metallic mask layer.
 23. The method of claim1, wherein said at least one mask layer comprises a stack, from bottomto top, of a metallic mask layer and a dielectric material layer. 24.The method of claim 1, wherein said at least one mask layer consists ofa dielectric mask layer.
 25. The method of claim 1, wherein said atleast one mask layer consists of a metallic mask layer.
 26. The methodof claim 1, further comprising removing said remaining portions of saidpatterned mask layer selective to remaining portions of said another ofsaid two mask layers after said transferring of said derived pattern.